import java.util.*;
public class Example2_5{
    public static void main(String args[]){
        int start = 0,end,middle;
        int a[]={12,45,20165215,67,89,123,-45,67};
        int N =a.length;
        for(int i=0;i<N;i++){//选择法排序数组
        for(int j=i+1;j<N;j++){
            if(a[j]<a[i]){
              int t=a[j];
              a[j]=a[i];
              a[i]=t;
            }
          }
         }
         Scanner scanner = new Scanner(System.in);
         System.out.println("输入整数，程序判断该整数是否在数组中:");
         int number =scanner.nextInt();
         int count=0;
         end=N;
         middle=(start+end)/2;
         while(number!=a[middle]){
            if(number>a[middle])
              start =middle;
            else if(number<a[middle])
              end=middle;
            middle=(start+end)/2;
            count++;
            if(count>N/2)
              break;
          }
          if (count>N/2)
            System.out.printf("%d不在数组中.\n",number);
          else
            System.out.printf("%d在数组中.\n",number);
      }
}

